Application note · February 2025

Advanced in vitro model for airway microbiota culture

Lung³Gel is a 3D in vitro model of the airway mucus layer for studying airway microbiota dynamics and drug permeability across mucus. It comes in physiological and cystic fibrosis-like formulations.

Lung³Gel

Airway · Cystic fibrosis · Drug permeability

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Lung³Gel

Model Lung³Gel, 3D airway mucus model, physiological and cystic fibrosis-like

Organisms Staphylococcus aureus and Pseudomonas aeruginosa

Compared with Mueller-Hinton broth; PermeaPad barrier without mucus

Readouts Colony counts (CFU), confocal microscopy, drug permeability

Competing bacteria coexist in Lung³Gel

Two competing airway pathogens, Staphylococcus aureus and Pseudomonas aeruginosa, were cultured in Lung³Gel and in Mueller-Hinton (MH) broth.

Coexistence

Bar chart of colony counts of S. aureus and P. aeruginosa in MH broth and in Lung³Gel; no S. aureus colonies in MH broth. — **Colony counts (CFU/mL)** of *S. aureus* and *P. aeruginosa* in MH broth and in Lung³Gel, labelled Air³Gel, its former name. * 0 CFUs.

Like in the human body, competitive bacteria coexist in Lung³Gel, which is not seen in traditional media.

Study: Pacheco et al., Advanced Functional Materials 2023, Heterogeneity governs 3D-cultures of clinically relevant microbial communities

Bacteria in the gel

Confocal microscopy image of bacteria growing in Lung³Gel. — **Confocal image of bacteria growing in Lung³Gel.**

Confocal microscopy of the same study shows the bacteria growing within the gel.

Mucus changes how drugs cross the barrier

Drug permeability was measured across the PermeaPad barrier with and without a layer of Lung³Gel on top.

Drug permeability

PermeaPad set-up with and without mucus, apparent permeability of each tested drug, and a chart of drugs with reduced, increased or unchanged permeability. — a PermeaPad set-up without and with the mucus layer. b Apparent permeability of each drug. c Drugs whose permeability was reduced, increased or unchanged by mucus.

The presence of Lung³Gel led to the reduction of diffusion of 51% of tested drugs, but also increased the permeability of 9% of tested molecules.

Study: Butnarasu et al., Pharmaceutics 2023, Permeability assessment of a high-throughput mucosal platform

Key features

Physiologically relevant Replicates airway mucus properties, such as chemical composition, nutrient content and viscoelasticity.
Condition-specific Available in physiological and cystic fibrosis-like formulations.
Microbiota-friendly Supports growth of key species, e.g. Pseudomonas aeruginosa, Staphylococcus aureus and Klebsiella pneumoniae.
Lab-compatible Ready for standard equipment and high-throughput setups.